This invention relates to a tubular belt conveyor having an endless belt the larger part of which is made to a tubular shape for carrying powdery materials by packing up them therein, and particularly relates to a supporting device for smoothly forming the endless belt to a tubular shape and a rolling up means for smoothly rolling up the larger part of the endless belt.
Conventionally, a tubular belt conveyor which is provided with an endless belt the larger part of which is formed to a tubular shape for carrying powdery materials without scattering them by packing up them wholly therein, which can carry those materials without being moistened by rain, being blown off by wind, even if it is installed in the outdoor, and which can be curved the carrying path freely, and can perform material carrying operation successively, even if the carrying path has steep inclination, has been already well-known.
In FIGS. 1 to 5 there is shown a conventional tubular belt conveyor. The reference number 1 designates an endless belt, for example, made of rubber which is, from manufacturing stage, bestowed liability, because of its natural elasticity to roll up itself, to form a tubular shape by overlapping both side end portions 1' and 1" with each other, and on a drive roller 2 arranged at the upper part of the belt conveyor and on a follower roller 3 located at the lower part thereof flattened parts of the belt are wound up.
The reference number 4 designates supporting frames which support the tubular formed part of the belt 1 at every predetermined intervals and guide it. Each of the supporting frame 4 is, as shown in FIG. 3, separated to two parts, an upper chamber 4a and a lower chamber 4b. In the inside of each of the chambers a plurality of belt shape maintaining rollers 5 (in the embodiment of the invention six rollers are provided) are disposed symmetrically so that they may be arranged on the circumference of a circle with approximately equidistance therebetween.
The belt 1 which is flattened on the lower follower roller 3 is gradually rolled up by self-rolling up liability caused by its elasticity and by introduction of a belt rolling up means which comprises a plurality of belt rolling-up rollers 6 disposed between the follower roller 3 and the belt shape maintaining rollers 5 at the lower end of the conveyor so that they may be arranged substantially on the circumference of a partial circle.
On the while the belt 1 packs up the materials to be carried which are fallen from a hopper 7, and the belt of going path 1a formed to a tubular shape passes through each of the upper chambers 4a of the respective supporting frames 4.
Then, the materials 8 to be carried are thrown onto a receiving tab 9, while the belt 1 is being travelled on the drive roller 2 and spreaded to a flattened plate shape by a belt spreading device (not shown) composed approximately in symmetrical relation with the above described belt rolling up means. The belt spreading device is disposed between the supporting frame 4 located at the front and the drive roller 2.
Next, same as the afore-described, the belt 1 is rolled up to a tubular shape and descends passing through each of the lower chambers 4b of the respective supporting frames 4. Then the belt 1 makes its rounds passing on the follower roller 3, after its being spreaded to form a flattened plate shape as same as the above described manner.
The tubular belt conveyor mentioned the above, in general, as shown in FIG. 4, both of the side end portions 1' and 1" of the belt 1 are smoothly overlapped immediately before the belt 1 enters to the circumference of the circle formed by the belt shape maintaining rollers 5 in the chamber located at the rearest position, and the belt 1 is completely rolled up when it passes through the circumference of the circle formed by the belt shape maintaining rollers 5.
However, as shown in FIG. 5 in the case of the materials 8 to be carried from the hopper 7, according to the amount of the materials 8 and physical property thereof, the marginal end portion of the inner side end portion 1" contacts with the inside of the outer side end portion 1', and when the belt 1 is rolled, those contact portions are frictionally moved, so that those portions are badly worn and extremely damaged.
In addition, in the case of extremity those contacting portions are puffed up with each other not to be smoothly rolled up to cause those end portions 1' and 1" to damage and life time of the tubular belt conveyor is remarkably shortened because of overstrains burdened on the belt shape maintaining rollers 5 at the lower part, the belt 1 and the drive means of the conveyor. In particular case there occurs even inverse overlapping with the upper and the lower side end portions.